Edwarbs



Patented ug.` l2, 193@ STATES PATENT OFFICE* NELSON EDWARDS, OF RED BANK, NEW JERSEY, ASSIGNOR T TRIPLEX SAFETY GLASS COMPANY OF NORTH AMERICA, 0F CLIFTON, NEW JERSEY, A CORPORATION 0F DELAWARE SEPARATION OF LAMINATED GLASS Application lcd January 80, 1929. Serial No. 336,133.

Laminated glass, composed of a'sheet of `celluloid between two sheets of glass to which the celluloid is strongly adherent, must be free from imperfections such as are caused by a bubbles of air or dust or anything other than celluloidand equally transparent cement between the two sheets of glass. Methods of manufacture of laminated glass have not reached such a degree of perfection that imA perfections of this character can always be prevented. That which causes such an imperfection is sometimes not apparent or is overlooked during the process of manufacture and is discovered only when the laminated glass is inspected after manufacture. The result is that there is produced some laminated glass which is not marketable and in which the glass represents a material item of cost. If the adhesion of the celluloid and the glass is permanent, asis to be desired, it is practically impossibleto separate the two sheets of glass without breaking. It is the object of this invention to provide a method by which the separation of tne laminated glass can be effected economically and with a minimum of breakage. In accordance with the invention the glass to be separated is placedl in a bath of cold water, that is, of Water at normal or room temperature, and both temperature and p ressure are gradually increased until the temperature is raised to about 2500 F. so as to produce a 'decomposition' and'.

thereby produce a bubbly or porous structure in the celluloid. The bath'having been maintained for a timesuiiicient to bring about such structure and permit the hot Water to circulate through the bubbly or porous structure and effect the separation of the glass from the celluloid, the pressure and the temperature are gradually reduced to normal atmospheric pressure and normal room temperai ture. The glass is'then removed from the bath and the two sheets can then be sepa- .rated readily. The lgradual raising of the temperature and pressure and the gradual lowering of the same while circulation of the water is maintained are necessary to rprevent 'the setting up of molecular stresses in the glass which would orrmight produce fracture. The invention will be more ullv ex- The apparatus comprises a tank a capable of withstanding an internal pressure of about 450 pounds and provided with a removable door b which may be bolted to a flange as indicated at Z1. The tank is provided with a v water inlet c, a Water outlctc, a steam inlet al, a safety valve e, a pressure gage f and a Water gage g, all with suitable connections. The water inlet c, connected to any suitable source, terminates within the tank a in a section c2 open at both ends. The steam pipe d preferably enters the tank through the Water inlet and terminates, as at d', in a pipe within the open ended section 02. The tank is also provided with a track L adapted to receive a wheeled car or rack i suitably constructed to receive the sheets of glass, indicated at k, which are to be separated. In the practice of the method the rack z', loaded with the glass to be separated, is run into the open and empty tank a. The door b is then iastened in place, precautions being taken to secure the door so tightly that there shall be no leakage when the required pressure is developed Within the tank. When the glass is in place the tank is filled, through the inlet pipe 0,'with water at normal room temperatureuntil all of the glass on the rack is submerged. Steam is then admitted through the pipe al, usually at about 40 pounds pressure. As the steam issues from the pipe d within the open ended section c2 of the water pipe,

it causes the water in the tank to circulate,

, sheets of glass from the celluloid. Tt will be 'found usually'that at the end of about onehundred minutes or more the separation oit the glass will have been accomplished generally with more or less disintegration ot the Celluloid. lVhen the glass has been subjected for the required time to the act-ion ot the hot u'ater the tank and its contents are allowed to cool or are cooled gradually by theaddition of cold Water` the entire charge being eventually drawn olf through the outlet o. The door ot the tank is then removed, the rack with its load of glass is Withdrawn and eaeh sheet ot the laminated glass is handled separately to complete the separa-tion of the two sheets. lt may be necessary sometimes to start the separation ot the two sheets ot glass by the introduction of a knife blade between them. but ordinarily it Will be found that the two sheets separate Without this.

l claim as my invention:

l. The method of separating' laminated glass which consists in placing a sheet of laminated glass comprising sheet-s of glass and an interposed sheet of Celluloid in a bath ot cold Water, gradually raising the temperature to produce a bubbly or porous structure in the Celluloid, maintaining the temperature of the bath to permit the heated Water to circula-te in the bubbly or porous structure of the Celluloid` gradually lowering the temperature of' the bath, and finally removing the glass from the bath.

2. The method of separating laminated glass which consists in placing a sheet of laminated glass comprising sheets of glass and an interposed sheet et Celluloid in a bath of cold Water7 introducing steam into the bath until the temperature of the bath has been raised to produce a bubbly or porous structure in the Celluloid, maintaining the temperature of the bath to permit the heated Water to circulate in the bubbly or porous structure of the Celluloid, gradually lowering the temperature ot the bath, causing the Water to circulate during the raising, maintaining and lowering of the temperature and finally removing the glass from the bath,

3. The method of separating laminated glass which consists in placing a sheet of laminated glass comprising sheets of glass and an interposed sheet of Celluloid in a bath of cold Water Within a closed vessel7 introducing steam into the Water in the vessel until the temperature is raised to produce a bubblyor porous structure in the Celluloid and the pressure is also raised, maintaining the temperature of the'bath to permit the heated Water to vcirculate in the bubbly or porous structure of the Celluloid,v gradually lowering the temperature and pressure of the bath, causing'the Water to circulate in the vessel during thel raising, maintaining and loweringvof the temperature, discharging manana the Water from the "Vessel, and removing the glass'.

January A.. D. 19

29. NEllLSDN EDWARDS. 

